, people have paved over the front yards. >> reporter: district 4 supervisor katie tang wants to break up some of the concrete so she is asking for volunteers. you give the city about $200, they give you a new front yard. >> we'll help you do the prep. we'll help you break up the concrete, help you figure out what kind of plants and species will survive at sunset. >> reporter: but the pitch doesn't end with more appealing streets. >> we're looking citywide at opportunities to better manage stormwater. we have a combined system so stormwater and sewage gets into the same pipes. >> reporter: we have taken you down into the aging sewer system. >> that was the flow line sometime not too long ago. >> reporter: we have also shown you what happens when a storm overwhelms it. so when you see a concrete yard, remember, that leaves the rain with only one place to go. >> while each home doesn't seem like a large area? >> cumulatively it adds up to millions of gars every year. >> reporter: so the city wants volunteers to break up the sunset. >> there are folks who want to do this but didn't know how.